Apparently there was a tool called xcodeindex in earlier XCode versions to index projects from the command line. However there doesn't seem to be one even after I install the command line tools in Preferences.
Am I just not finding it? Is there any other way to force indexing a projects?
(The problem is that If I download a project from for example SVN and try to do an xcodebuild on it without opening it in XCode first it will fail with a message like the specified scheme does not exist in the project. If I open it in XCode first and let it index a little, xcodebuild will not fail.)
The solution: there is no need to index the project. By going into the "Manage Schemes" menu in XCode and checking the "shared" checkbox next to the particular scheme, the problem will be solved.